1. Field of the Invention
The present invention relates to a process for the production of an optically active amino alcohol which is useful for synthesis of natural products and is useful as intermediates for drugs and agricultural chemicals.
2. Description of the Related Art
Optically active amino alcohols are the compounds which are not only useful for synthesis of natural products (Non-patent document 1) but also very useful as intermediates for drugs and agricultural chemicals (Patent Document 1, Patent Document 2, Non-patent Document 2 and Non-patent document 3).
Those optically active amino alcohols are able to be synthesized by i) reduction of keto-enamines (Patent Document 3), ii) reduction of isoxazolines and isoxazoles (Non-patent Document 4), iii) reduction of β-aminocarbonyl compounds (Non-patent Document 5), iv) reduction of ketopyridines (Non-patent Document 6), v) reduction of α,β-unsaturated ketones (Non-patent Document 7), vi) reduction of α-cyano esters (Non-patent Document 8), etc.
Methods mentioned in i) to vi) may be expressed by the following reaction formulae.
i) Reduction of keto-emanines 
ii) Reduction of isoxazolines and isoxazoles 
iii) Reduction of β-aminocarbonyl compounds 
iv) Reduction of ketopyridines 
v) Reduction of α,β-unsaturated ketones 
vi) Reduction of α-cyano esters 
In the above reaction formulae, i) to iii) are carried out using the reagent such as lithium aluminum hydride (LiAlH4), sodium cyanoborohydride (NaCNBH3) or nickel-aluminum alloy (Ni—Al alloy) in an equivalent or more amount to the substrate. In addition, the reagent used is hard to handle and is used in an equivalent or more amount to the substrate and, therefore, excessive amount of the reagent is to be treated during the after-treatment whereby there is a problem that the working efficiency is bad. Therefore, the methods of i) to iii) contain the step which is believed to be a burden in conducting in an industrial scale and with economy.
In the meanwhile, methods where the reduction reaction is carried out by way of catalytic reaction are reported in iv) to vi) for solving the above problem. However, the methods mentioned in iv) to vi) have a problem that the product is a racemate.
Accordingly, there has been demanded a method where an optically active amino alcohol is synthesized at a low cost, with a good working efficiency, in an industrially applicable manner and in high yield and high selectivity.
Patent Document 1: U.S. Pat. No. 005,491,253 A
Patent Document 2: U.S. Pat. No. 4,454,332
Patent Document 3: JP 61/246176 A
Non-patent Document 1: Angew. Chem., Int. Ed., 1981, 20, 601
Non-patent Document 2: Tetrahedron Lett., 1980, 2783
Non-patent Document 3: J. Org. Chem., 1994, 59, 4040
Non-patent Document 4: J. Org. Chem., 1987, 52, 1043
Non-patent Document 5: J. Org. Chem., 1985, 50, 4052
Non-patent Document 6: Helv. Chim. Acta, 1962, 45, 729
Non-patent Document 7: J. Org. Chem., 1977, 42, 650
Non-patent Document 8: J. Org. Chem., 1963, 28, 3129